function set_background(){
	//get farleft and content divs
	var div_farleft = document.getElementById("left");
	var div_content = document.getElementById("mycontent");
	//get high of content div
	var content_height = div_content.getAttribute("height");

	//set background and height of farleft div
	div_farleft.setAttribute("height","800px");
	div_farleft.setAttribute("backgroundColor", "#ffffff");
}